Conventionally, the fuel cells stacked in the same fuel cell stack are all orientated toward the same direction, i.e. either all being arranged with their anode facing upward and cathode facing downward, or the other way around. In addition, since for each fuel cell in the stack, it is required to have fuel gas flowing only through its anode and oxidant gas flowing only through its cathode without causing the fuel gas to mix with the oxidant gas, any two neighboring fuel cells are generally being separated from each other by the use of interconnect having gas grooves machined thereon. However, the machining cost in addition to the material cost of the interconnect used in those conventional fuel cell stacks will directly cause the overall manufacturing cost of the fuel cell stack to increase, not to mention that the overall volume of the fuel cell stack will increase also. In addition, since typically a group of individual fuel cells along with their interconnect are welded, soldered or otherwise bonded together into a single unitary stack by the use of a specific sealing material, accordingly if one cell fails to function normally and must be removed and replaced, not only the removal of such a malfunctioning fuel cell can be a very difficult task, but also it is more than likely that the remaining fuel cells are destroyed in the process. This leads to significant losses in time and money.